erythromycin at a glance
Medicine class
Macrolide antibiotic.
Main role
Treating or preventing susceptible bacterial infections; it does not treat viral infections.
Taking the tablets
Swallow gastro-resistant or enteric-coated tablets whole with water; do not crush or chew them.
Important safety check
Heart-rhythm risks and medicine interactions should be reviewed before treatment.
What is erythromycin used for?
Oral products are licensed for susceptible bacterial infections and certain preventive uses.
Respiratory tract infections, including some forms of bronchitis and pneumonia.
Ear, eye, oral and dental infections.
Skin and soft-tissue infections, including impetigo, cellulitis and pustular acne.
Certain gastrointestinal, bone, genitourinary and sexually transmitted infections.
Selected prevention around surgery, burns or trauma, and prevention of recurrent rheumatic fever.
How does erythromycin work?
Erythromycin binds to the bacterial 50S ribosomal subunit and suppresses protein synthesis. This usually stops susceptible bacteria growing and may kill them, depending on the organism and antibiotic concentration.
erythromycin preparations and strengths
Gastro-resistant tablet
Route: Oral
Strengths: 250 mg
Tablet
Route: Oral
Strengths: 250 mg
How to take erythromycin
Follow the dispensing label and instructions for the specific product supplied.
Swallow coated tablets whole with water; do not crush or chew them.
It can often be taken with food if it causes stomach upset, but follow product-specific instructions.
Complete the prescribed course unless a clinician tells you to stop.
Avoid grapefruit and grapefruit juice because they can increase erythromycin exposure and side effects.
erythromycin side effects
Common or expected effects
- Nausea or vomiting
- Diarrhoea
- Abdominal discomfort or cramps
- Reduced appetite
- Bloating or indigestion
Get urgent medical advice
- Severe allergic reaction or swelling affecting breathing or swallowing
- Blistering, peeling or widespread severe rash
- Abnormal heartbeat, chest pain, fainting or seizure
- Severe or prolonged diarrhoea, particularly with blood or mucus
- Jaundice, dark urine or pale stools suggesting liver injury
- Severe abdominal pain suggesting pancreatitis
- New tinnitus, hearing loss or marked balance disturbance
erythromycin in pregnancy
Erythromycin can be used during pregnancy when recommended by a doctor. UK pregnancy information is reassuring overall, but product information notes conflicting observational evidence about a possible small risk after early-pregnancy exposure. Oral erythromycin is not considered adequate treatment to prevent congenital syphilis.
erythromycin while breastfeeding
Erythromycin can generally be used while breastfeeding a full-term, healthy infant with monitoring. Seek specialist advice if the infant is premature or unwell; watch for diarrhoea, vomiting, oral thrush, rash, poor feeding or unusual irritability.
erythromycin interactions
Erythromycin inhibits CYP3A4 and can raise concentrations of several medicines. Ask a pharmacist or prescriber to check all prescribed, non-prescription and herbal products.
Simvastatin and lovastatin
The combination can markedly increase statin exposure and the risk of muscle injury or rhabdomyolysis; selected product information lists simvastatin as contraindicated.
Domperidone, pimozide and certain antihistamines
These combinations can cause serious QT prolongation and ventricular arrhythmias and are contraindicated with the selected products.
Common questions about erythromycin
Answers are fully visible for fast scanning and source review.
Can I take erythromycin if I am allergic to penicillin?
Erythromycin is chemically different from penicillin and may be an alternative in some situations, but the prescriber must check the infection and any previous macrolide allergy.
Can erythromycin tablets be crushed or chewed?
No. The selected gastro-resistant or enteric-coated tablets should be swallowed whole with water.
Does erythromycin affect contraception?
It does not directly stop hormonal contraception working, but vomiting or severe diarrhoea can reduce pill protection; follow the contraceptive packet instructions.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.